Endodontic cutter



Oct. 5, 1965 l.. J. ROSEN 3,209,458

ENDODONTl C CUTTER Filed Dec. 5. 1960 INVENTOR. LOU/J d. /POJE/V United States Patent O 3,299,458 ENDODONTIC CUTTER Louis J. Rosen, 3465 Cote des Neiges Road, Montreal, Quebec, Canada Filed Dec. S, 1960, Ser. No. 73,891 4 Claims. (Cl. 32-40) This invention relates to a method of securing a silver point in the root canal of a tooth in a manner to prevent its accidental displacement thereafter.

In the treatment of the pulp of a tooth contained in the root canal, it is essential that there first be a complete surgical removal of the contents of the root canal, followed by sterilization of the canal and then the ultimate obliterat-ion of the canal by a good root canal iilling. To yachieve this, it is the standard practice today for certain teeth, to employ a sterling silver point as the root canal lling. The size of the silver point corresponds to the dimensions of the root canal. The silver point is inserted into the canal so that it will completely till the canal to the apex of the tooth, thus providing a good hermetical seal.

-In order to secure the correct size of silver point, X-

rays are taken, and after much trial and error, the cor-- rect size is selected. The selected silver point should be insertable so as to reach as near to the apex point of the tooth as possible.

The silver point'thus selected is placed in the root canal with the prong end of the point projecting from the occlusal surface of the tooth. The point is now cut flush with the occlusal surface and this will now serve as a gui-de. The occlusal surface is the biting surface of the tooth. Thereafter, the silver point is cemented in place, the floor of the pulp chamber being packed with base plate guttapercha to a height of about 2 or 3 millimeters, thus securing the point or points in a single or multi-rooted tooth, in position and checked again with an X-ray.

At this stage of the treatment, the silver point protrudes above the surface of the guttapercha through the pulp chamber to the occlusal surface of the tooth. It is self-apparent that the pulp chamber is a very nar-row space with-in which it is diicult to do any work. However, it is necessary that the silve-r point shall not protrude above the guttapercha because in the course of preparing for and the insertion of the coronal lling, there is a tendency to disturb the protruding silver point. Any such disturbance may cause a movement of the silver point which would then produce a void in the apical end of the root canal, breaking the hermetical seal, thus undoing all of lthe work up to this point 4in the selection and insertion of the silver point to prevent such avoid.

Heretofore because of the small space available to work in, various techniques have been employed for cutting olf as much of the protruding portion of the silver point as is possible. This has been tried by using scissor points, by use of a bur applied to the protruding point in the pulp chamber. Another method is to make a nick in the silver point before it is placed into position in the root canal at a point apical to the floor of the pulp chamber. After the point is cemented into the root canal, by twisting the protruding point from side to side, it would become separated from the rest of the point. But all these techniques involve the danger of disturb-ing the silver point and therefore running the risk of creating a void in the apical end of the root canal. Another disadvantage of the last mentioned technique is that should it become necessary at some later date for some reason to remove the point from the canal there will be no means of gripping the point to retrieve it.

Thus, in the case of use of the scissors, there is a tendency to produce a force which accidentally pulls the silver point away from the apex. In the case of the bur, when it engages the silver point it also has the danger of applying a longitudinal force which would remove the silver point from the apex. When a nick is made in the silver point before cementing it into the canal, a Carborundum disc is applied against the silver point several millimeters below the floor of the pulp chamber and then a twist back and forward cuts the point. However, this obviously has a tendency to sufliciently disturb the wire to cause it to be moved and produce a void.

In accordance with my invention, I have designed an instrument -of such a size that it can be easily inserted in the narrow space of the pulp chamber just above the guttapercha which rst grips the wire and simultaneously by a novel design of the cutting edges produces no longitudinal force, or if any such longitudinal force is produced, it is in the direction toward pushing the silver point inwardly so that during the cutting by the cutting edge of the instrument the silver point is not disturbed and the silver point is clipped ush with the guttapercha surface.

Accordingly, an object of my invention is to provide a novel method for ensuring that the silver point is locked a-nd held in position in the root canal substantially up to the apex.

Another object of my invention is to produce a novel instrument to cut off the protruding silver point without outward longitudinal force applied to the silver point.

Still another object of my invention is to provide a novel instrument which can be inserted within the narrow space lof the pulp chamber.

Another object of my invention is to provide a novel instrument and method of cutting the protruding portions of the silver poi-nt flush with the guttapercha surface.

In cutting off the point flush with guttapercha surface, several millimeters of the silver point are still embedded in the guttapercha mass. Should it become necessary to remove a point from the canal for retreatment of the canal at a later date, the guttapercha can be softened by means of a hot instrument and teased way from the environs of the projecting silver point and thus it is possible to grip the end of the point with an instrument for its removal.

Ihese and other objects of my invention will be more clearly understood from the detailed description which lfollows, in which:

FIGURE 1 is a schematic view of one form of instrument used in carrying out my invention.

FIGURE 2 is a front view of that portion of the instrument which is insertable in the pulp chamber of the tooth.

FIGURE 3 is a sectional view of the nose of the cutter.

FIGURE 4 is a plan view of FIGURE 3 through line 4-4 of FIGURE 3.

Referring lirst to FIGURE 2, a schematic view of a tooth 1 is shown in which the pulp chamber of the tooth 2 has been cleaned to achieve complete debridemcnt and sterilization of the root canal 3. As already stated, X-rays having been ltaken to determine the length of the root canal, a proper size silver point is selected and inserted in the root cana-l and forced apically until binding is felt. The protruding end of the silver point is cut ush with the occlusal surface of the tooth to act as a guide. X-rays are now taken to check the position the silver point holds with relation to the apex of the tooth. If position is satisfactory, the next step -is proceeded with which is the cementing of the silver point into position in the root canal. This is accomplished as follows: an antiseptic root canal sealing cement is prepared. The apical part o-f the silver point is buttered with a little cement. The silver point 3 is now placed into the root canal with a pumping action and forced apically until the coronal portion of the silver poi-nt 4 is flush with the occlusal surface of the tooth. Base plate guttapercha 5 to a height of about 2-3 millimeters is packed against the floor of the pulp cavity 2. This now secures the silver point 4 in position and to ensure this a further X-ray is taken of the silver point in position.

Having determined that the silver point is properly cemented to the root canal, it is now necessary to remove the protruding portion of the silver point. To this end the instrument comprising two legs 6 and 7 is inserted into the pulp chamber of the tooth, as shown in FIGURE 2, -until the lower edges of transversely extending jaws 8 and 9 touch the upper surface of the guttapercha along a transverse cutting plane dened by their forwardmost ends.

The legs 6 and 7 carry the gripping surfaces 10 and 11 which may be precision made members or may be a .precision semicircular transverse recession of the legs 6 and 7 as best shown in FIG. 4.

At the lowermost edge of legs 6 and 7, the cutting edges 12, 13 protruding from the legs are constructed to simultaneously grip the lowermost protruding portion of the silver point 4 so that substantially simultaneously with the gripping of the silver point 4, the silver point is cut by the cutting edges 12 and 13 flush with the exposed surface of the gut-tapercha 5.

In a preferred form of my novel tool, the cutting edges 12 and 13 are bevelled :so that as the silver point 4 is engaged and cut, a longitudinal force is applied on the silver point in the apical direction.

Although the construction may be such as to apply no force other than the transverse gripping force on the silver point, a somewhat downward force to ensure that the silver point is, if anything, kept secure in the r-oot canal may be applied.

As will now be obvious to those skilled in the art, the remaining portions of my novel scissor-like tool may adopt any desired form and so is shown only in schematic form in FIGURE 1. The essential features of the tool reside in the small size of the legs of the cutter carrying the .cutting edge and the gripping edge so that it can be readily insertable into the cusp chamber to engage and cut the protruding portion of the silver point so that it is flush with the guttapercha surface and does not apply any force which would disturb the silver point in its cemented position.

I claim:

1. A scissor-like tool for insertion in the pulp cavity of a tooth, said tool having a pair of handles, a pair of legs longitudinally extending in substantial alignment with said handles, said legs being movable with respect to each other, the forward end of each of said legs having a transversely extending jaw, defining a transverse cutting plane at its forwardmost end, said legs and jaws having a sutliciently small cross-section to permit the entry of said legs into the pulp cavity of a tooth, with said cutting plane positioned at the inner termination of the pulp cavity, and in transverse alignment with the lowermost protruding portion of a silver point secured to the root canal, the inner edges of said jaws facing each other, and having cutting edges movable together within said cutting plane, for simultaneously gripping the pro-truding portion of the silver point within said cutting plane and cutting the silver point flush with the inner termination of the pulp cavity, said jaws shaped to prevent apical dislodgement of the silver point from the root canal during the cutting thereof, and said legs including gripping surfaces longitudinally extending rearward of said cutting surfaces, said gripping surfaces transversely recessed from said cutting edges to grip and remove the cut portion of the silver tip.

2. A scissor-like tool as set forth in claim 1, wherein said cutting edges when brought together meet along a tra-nsverse line with-in said cutting plane, and in planar alignment with the forwardmost ends of the transverse jaws, said jaws having beveled portions meeting their respective cutting edges and shaped to limit the longitudinal cutting forces in the apical direction.

3. A scissor-like tool as set forth in claim 1, wherein said gripping surfaces comprise semi-circular recessions, dimensioned to cooperat-ively engage the cut-away end of the silver point subsequent to the engagement of said cutting edges.

4. A scissor-like tool as set forth in claim 1, wherein said cut-ting edges when brought together meet along a tran-sverse line within said cutting plane, and in planar alignmentV with the forwardmost ends of the transverse jaws, said jaws having beveled portions meeting their respective cutting edges and shaped to limit the longitudinal cutting forces in the apical direction, said gripping surfaces comprise semi-circular recessions, dimensioned to cooperatively engage the cut-away end of the silver point subsequent to the engagement of said cutting edges.

References Cited by the Examiner UNITED STATES PATENTS 674,419 5/01 Kinsman 32-15 713,470 11/02 Martin 32-46 1,328,131 1/20 Davis 32-46 1,471,422 10/2-3 Shearer 32-46 1,587,464 6/-26 Beghetti 30--186 1,711,952 5/29 Kulik 32-415 RICHARD A. GAUDET, Primary Examiner.

ROBERT E. MORGAN, Examiner. 

1. A SCISSOR-LIKE TOOL FOR INSERTION IN THE PULP CAVITY OF A TOOTH, SAID TOOL HAVING A PAIR OF HANDLES, A PAIR OF LEGS LONGITUDINALLY EXTENDING IN SUBSTANTIAL ALIGNMENT WITH SAID HANDLES, SAID LEGS BEING MOVABLE WITH RESPECT TO EACH OTHER, THE FORWARD END OF EACH OF SAID LEGS HAVING A TRANSVERSELY EXTENDING JAW, DEFINING A TRANSVERSE CUTTING PLANE AT ITS FORWARDMOST END, SAID LEGS AND JAWS HAVING A SUFFICIENTLY SMALL CROSS-SECTION TO PERMIT THE ENTRY OF SAID LEGS INTO THE PULP CAVITY OF A TOOTH, WITH SAID CUTTING PLANE POSITIONED AT THE INNER TERMINATION OF THE PULP CAVITY, AND IN TRANSVERSE ALIGNMENT WITH THE LOWERMOST PROTRUDING PORTION OF A SILVER POINT SECURED TO THE ROOT CANAL, THE INNER EDGES OF SAID JAWS FACING EACH OTHER, AND HAVING CUTTING EDGES MOVABLE TOGETHER WITHIN SAID CUTTING PLANE, FOR SIMULTANEOUSLY GRIPPING THE PROTRUDING PORTION 